1. Field of the Invention
Photoresists have been used in the lithographic production of wide range of devices including integrated circuits such as LC and LSI, display devices such as LCD and EL device, printed boards, micro machines, DNA chips and micro plants. The present invention relates, particularly, to a photoresist stripping composition for removing photoresists from various substrates carrying the photoresists.
Amine compounds, with their alkaline and nucleophilic natures, have been used for cleaning integrated circuits, liquid crystal display devices and printed boards and for removing photoresists applied on the substrates of these devices. The present invention further relates to a novel amine compound optimum for use in these purposes, a production method thereof, a cleaning composition and a photoresist stripping composition containing the novel amine compound.
2. Description of the Prior Art
Alkaline stripping compositions have been conventionally used for removing photoresists. For example, TOK106 available from Tokyo Oka Co., Ltd. comprises an alkanolamine and dimethyl sulfoxide, and EKC265 available from EKC Technology Co., Ltd. comprises an alkanolamine, hydroxylamine, catechol and water. U.S. Pat. No. 4,276,186 discloses a composition comprising N-methylpyrrolidone and ethanolamine, and Japanese Patent Application Laid-Open No. 4-289866 discloses a composition comprising an alkanolamine and hydroxylamine.
These alkanolamines have been synthesized by the reaction of a corresponding alkylene oxide and ammonia as described in “Industrial Organic Chemistry”, 4th ed., p175, Tokyo Kagaku Dojin Co., Ltd. edited by Sakiyama Mitsuaki. These alkanolamines are very inexpensive because produced by a simple process. However, the use of the alkanolamine alone cannot meet the recent requirement in the production of semiconductor devices and liquid crystal display panels, particularly, with respect to the fine processing and short-term processing. To meet the requirement, Japanese Patent Application Laid-Open Nos. 11-194505 and 6-266119 disclose compositions containing hydroxylamine. The composition containing hydroxylamine shows a high resist removal. However, hydroxylamine is disadvantageous because easily decomposed, this making the purification thereof difficult to significantly increase its cost.
As a compound free from these drawbacks and capable of effectively enhancing the resist removal, Japanese Patent Application Laid-Open No. 2000-250230 discloses hydroxymethylamine. Although, hydroxymethylamine is stable as compared with hydroxylamine, the hydroxyl group contained therein increases the viscosity. Recently, semiconductor devices for semiconductor integrated circuits and liquid crystal display devices have come to be produced from various materials, requiring a photoresist stripping composition free from corrosion of various substrate materials.